CA1239873A

CA1239873A - Phospholipid-emulsified prostaglandin composition

Info

Publication number: CA1239873A
Application number: CA000471947A
Authority: CA
Inventors: Kazumasa Yokoyama; Takashi Imagawa; Yutaka Mizushima
Original assignee: Green Cross Corp Japan; Taisho Pharmaceutical Co Ltd
Current assignee: Taisho Pharmaceutical Co Ltd; Welfide Corp
Priority date: 1984-01-12
Filing date: 1985-01-11
Publication date: 1988-08-02
Also published as: EP0150732A2; JPS60149524A; ES8605165A1; ES539828A0; DE150732T1; US4684633A; EP0150732B1; JPH0818989B2; EP0150732A3; DE3570596D1

Abstract

M-37-37057C/KT/84.

ABSTRACT OF THE DISCLOSURE

A prostaglandin emulsion composition comprising a prostaglandin emulsified with a phosphatidylethanol-amine-free phospholipid, the composition being suitable for intravenous administration.

Description

~Z3~

PHOSPHOLIPID-EM~LSIFIED PROSTAGLANDIN COMPOSITION

FIELD OF T~E INVENTION
.
This invention relates broadly to phospholipid-emulsified prostaglandin compositions. More particularly, the invention relates -to a pros-taglandin-con-taining oil-in-water emulsion emulsi~ied with a phosphatidylethanol-amine-free phospholipid fraction.

BACKGROUND OF THE INVENTION

Prostaglandins are generally known to have pharmacological actions. For example, these compounds have blood pressure lowering and antilipolytic actions, and also inhibit platelet aggregation. Therefore, prostaglandins are of value in the treatment of hyperten sion, thrombosis, asthma, and gastric and intestinal ulcers, for induction of labor and abortion in pregnant - 15 mammals, and for prophylaxis of arteriosclerosis.
Prostaglandins are lipid-soluble substances which are obtainable in very small quantities from various organs of animals which secre-te prostaglandins endocrinally. These compounds have biological actions/
for e~ample, smooth muscle contracting action on uterine muscle, isolated small intestine, etc., hypotensive or pressor action, antilipolytic action, gastric secretion inhibi-tory action, central nervous system action, ~23~8~73 platelet adhesiveness decreasing action, platelet aggre-gation inhibitory action, antithrombotic action, and stimulant action on epithelial prolieration and keratinization.
Although prostaglandins have these useful properties, pros-taglandin compounds present problems due to their chemical instability when they are to be exploited as drugs.
SUMM~Y OF THE INVENTION
The intensive research undertaken by the present inventors to overcome the instability of prostaglandins led to the finding that, when they are incorporated into an oil-in-water emulsion, these compounds are not only stabilized but also made adaptable to intravenous administration and tha-t the use of a phospholipid, which is free of phosphatidylethanolamine, as the emulsifier contributes further to the stability of prostaglandins. This invention has been conceived and developed on the basis of the above findings.
Accordingly, this invention provides a prostaglandin emulsion composition comprising a prostaglandin, as the disperse phase,emulsified in water as the continuous phase with phosphatidyle-thanol-amine-free phospholipid~

DETAILED DESCRIPTION OF THE INVENTION
The prostaglandins (hereinafter referred to for brevity as "PG") employed in accordance with this invention include the following compounds and their 5 derivatives.

Abbrevi-ation Chemical Name ..... _ .. .. . ~ . ....... .. _ .. _ _ _ PGF2~ (5Z, 13E, 15S)-9u, 11~, 15 - trihydroxy - prosta -5,13 dienoic acid PGE2 (5Z, 13E, 15S~ , 15 - dihydroxy - 9 - oxo -pros~a - 5, 13 - dienoic acid PGD2 t5æ, 13E, 15S) - 9~, 15 - dihydroxy - 11 - oxo -prosta - 5, 13 - dienoic acid PGFl~ (13E~ 15S) - 9~ , 15 - ~rihydroxy - prost -13 ~ enoic acid P&El ~13E, 15S) - llu, 15 - dihydroxy - 9 - oxo -prost - 13 - enoic acid PGAl (13E, 15S) - 15 - hydroxy - 9 - oxo - pros-ta -10, 13 - dienoic acid PGI2 (5Z~ 13E, 15S) ~ , 15 - dihydroxy - 6.9~ -epoxy - prosta - 5, 13 - dienoic acid PGBl (13E, 15S) - 15 - hydroxy - 9 - oxo - prosta -8(12), 13 - dienoic acid Preferred examples of these derivatives are the alkyl esters -thereof. The alkyl moiety of the alkyl ester of PG can be an alkyl group having 1 to 30 carbon atoms, preferably 1 to 15 carbon atoms and more preferably 3 to 10 carbon atoms. Examples oE the alkyl group include a methyl ~:3~

groupr an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and n-decyl group.
The above-described alkyl moiety (Cl 30 alkyl) may be replaced by a Cl 30 alkyl-COO-Cl 5 alkyl group or a Cl 30-OCO-C1 5 alkyl group. Examples of the Cl 5 alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, and an n-pentyl group.
The oil emulsion employed in accordance with this invention is exemplified, predominantly, by those consisting of vegetable oil (for example~ soybean oil, cotton seed oil, sesame oil, safflower oil and corn oil), phospho-. 15 lipid and water~ The proportions of these components may be such that the oil component accounts for about 5 to about 50 w/v percentl preferably 8 to 30 w/v percent, of the total emulsion and the proportion o~ the phospholipid component is about 1 to about 50 parts, preferably 5 to 30 parts, per lO0 parts of the oil component, the proportion of water being more or less optional. If desired, an auxiliary emul.sifier (for example, a fatty acid containing 6 to 22, preferably 12 to 20, carbon atoms or a physiologically acceptable salt thereof (for example, alkalimetal salts such as sodium - 123~3 salts and potassium salts and alkaline ear~h metal salts such as calcium salts~ in a proportion of up to about 0.3% lw/v)), a stabilizer (for example, a cholesterol compound such as cholesterol in a proportion of up to about 0.5% (w/v), preferably up to 0.1% (w/v), or a phosphatidic acid in a proportion of up to about 5~ ~w/v), preferably up to 1% (w/v~), a high molecular weight compound (for example, albumin, dextran, vinyl polymers, nonionic surfactants, gelatin, hydroxyethyl-starch, etc., in a proportion of about 0.1 to about 5 weight parts, preferably 0.5 to 1 weight part, relative to 1 weight part of PG), an isotonifying agent (for example, glycerin, glucose, etc.) in a proportion of about 0.1 to 10 w/v percent, preferably 1 to 8 w/v percent and so on may also be employed. While the proportion of PG in the fat emulsion may be adjustable within a certain range depending on the form of the emulsion and the intended use of the final composition, it is generally sufficient to incorporate a very small amount, for example, about 0.2 to 100 ~g/mQ, of PG in the emulsion.
Referring to the oil component and, for example, to soybean oil, it is a high purity soybean oil. Preferably, a high purity soybean oil (purity: at least 99.9~ as tri-glyceride, diglyceride and monoglyceride) obtainable by subjecting purified soybean oil to further purification by 3~

steam distillation is employed.
As the phospholipid, a phospholipid fraction free of phosphatidylethanolamines is employed. Such a phopholipid fraction can be obtained from egg yolk phospholipid and soybean phospholipid fractions, for instance, by subjecting the same to fractionation with an organic solvent in the conventional manner as described, for example, in D~Jo Hanahan et al: J. Biol. Chem., 192, 623-628 (1951~ and purifying the same fuxther with the aid of an inorganic adsorbent such as silica gel or alumina.
The phospholipid obtainable using such a procedure consists mostly of phosphatidylcholines (about 6 to 80 w/v percent), and may contain other phospholip ds 5u~h as phGsphatidylinositols, phosphatidylserines and sphingomyelin. If sufficient emulsi-fication cannot be accomplished with this emulsifier, anauxiliary emulsifier is employed.
Suitable fatty acids of 6 to 22 carbon atoms described hereinbeore as an example of the auxiliary emulsifier may be those that can be added to and are compatible with drugs. The fatty acid may be straight chain or branched chain, although a straight chain fatty acid such as stearic acid, oleic acid, linolic acid, palmitic acid, linoleic acid, myristic acid, etc., is preferred. The salts thereof are physiologically ~3~73 aCceptable salts such as salts with alkali metals ~such as sodium, potassium, etc.) and alkaline earth metals (such as calcium).
The stabilizer must be a substance which can be used in pharmaceutical preparations.
The albumin, vinyl polymers and nonionic surfactants which can be used as the high molecular weight compound component are preferably those mentioned below.
Thus, as re~ards albumin, human albumin is desixable from an antigenicity point of view.
Examples of vinyl polymers include polyvinyl pyrrolidone.
Suitable nonlonic surfac-tants include, a~nong others, polyalkylene glycols (for example, polyethylene glycols having an average molecular weight o~ about 1,000 to about 10,000, preferably ~,000 to 6,000), polyoxyalkylene copolymers (for example, polyoxyethylene-polyoxypropylene copolymers having an average molecular weight of about 1,000 to about 20tO00, preferably 6,000 to 10,000), hydro-genated caster oil-polyoxyalkylene derivatives (for example, hydrogenated castor oil-polyoxyethylene (40)-ether, (20)-ether and (lQ0)-ether), castor oil-polyoxyalkylene derivatives (for example, castor oil polyoxyethylene (20)-ether, (40)-ether, and (1003-ether) and so on.

~2~ '73 The fat emulsion of this inventlon is prepared, for example, by the following process.
Thusr predetermined amounts of prostaglandin (e.g~, PG I2 es-ter), phospholipid, and, if desired, the above-mentioned additives are mixed with a required amount o~soybean oil, and the mixture is heated at 40 to 75C to form a salution. A required amount of water is added to the solution, and the mixture is emulsified at 20 to 80C
by means of a conventional mixer (for example Homomixer) to give a crude emulsion. Stabilizers and isotonifying agents may be added at this stage.
The crude emulsion is then homogenized at 20 to 80C by using a homogenizer (for example, a pressure-jet type homogenizer such as Manton-Gaulin type homogenizer or an ultrasonic homogenizer) to obtain a homogenized, extremely fine fat emulsion containing the prostaglandin, which can be administered by intravenous injection. The emulsion has an average particle diameter of 1.0 ~m or less, preferably 0.1 to 0.5 ~m, and has an excellent stability against heat~sterilization and storage.
When a Manton-Gaulin type homogenizer is used as the homogenizer, for example, the homogenization of crude emulsion is carried out, for example, passing the crude emulsion through the said homogenizer 0 to 2 times ~L%~9~7~

at the first-stage pressure of 100 to 150 kg/cm2 and then 5 to 15 times under the second pressure of 400 to -700 kg/cm ~
The phospholipid-free prostaglandin composi-tion can be administered to animals including humans for the purposes for which prostaglandins are generally administered. The present composition i5 administered non-orally~ i.e., parenterally, and preferably by the intravenous route. The generally recommended administra-tion and dosage schedule is about 1 to about 50 ~g as PGin a single daily dose by sustained intravenous infusion at the rate of about 0.02 to about 1 ng/kg of body weight/minute.
In the phospholipid-emulsified P& composition according to this invention~ the PG has been stabilized and displays its pharmacological actions with greater efficiencies. This feature coupled with its greater focus selectivity allows clinicians to institute a more effective PG therapy than ever before.
Furthermore, the phospholipid-emulsified PG
composition according to this invention can be adminis-tered b~ an intravenous route, and since its pharma-cological actions and therapeutic efficacies are stable, therapeutic responses are elicited at reduced dosage ~L2~'73 levels, with a consequently reduced incidence of side effects.
In addition, adverse local reactions which have heretofore been encountered, such as swelling~ dull pain, redness, fever, etc., do not occur with the phospholipid-emulsified PG composition of this invention.
- The following examples are intended to illus-trate the phospholipid-emulsified PG composition of this invention in further detail but are by no means intended to limit the scope of the invention.
EXPERIl~ENTAL EXAMPLE
The intravenous LD50 value of the present composition according to Example 1 in rate was not less than 200 mQ/kg body weight for a 10~ emulsion and not less than 150 m /kg body weight for a 20% emulsion. It was administered by drip infusion at a conventional rate, no hemolytic reactions were encountered at all.
EXPERIMENTAL EXAMPLE
In the same manner as in Example 1, various prostaglandins and phosphatidylethanolamine-free phospholipids were used to produce prospholipid-emulsified PG compositions. The ~ormulations o~ these compositions are shown in Table 1 below. In order to evaluate the stability of PG in the compositions, the 7~

above compositions were subjected to high pressure, short time sterilization at 125C for 2.2 minutes to determine the percentage remaining of PG. As shown in Table 1 below, the stabilizing effects were determined for various prostaglandins and their esters, with the effects for alkyl esters being particularly remarkable.
The quantitative determination of PG was carried out by the fractional assay method using high performance liquid chromatography and the residual amounts of PG relative to pre-sterilization values were calculated and are shown as percentage remaining~
REFERENCE EXAMPLE
In 600 mQ of chloroform-methanol (1:1 by volume) was dissolved lO0 g of egg yolk phospholipid, followed by addition of 600 g of alumina under stirring. The stirring was continued for:5 minu-tes, at the end of which time the mixture was suction-filtered through-a G4 glass filter.
The alumina thus separated was washed with 400 mQ of chloroform-methanol (l:l by volume). The filtrate was pooled with the wash, and 200 g of fresh alumina was added to the combined solution with stirring. The stir-ring was con-tinued for S minutes, after which the mixture was suction-filtered through a G4 glass filter.
The alumina thus separated was washed with 200 mQ of chloroform-methanol (1:1 by volume). The filtrate was ~2~ 73 pooled with the wash and the combined solution was centrifuged.at 10,000 ppm for 10 minutes at a temperature of 4C. The supernatant was suction-filtered through a.1.0 ~ millipore filter and the solvent was diskilled oFf, whereupon at least 60 g of phosphatidylethanolamine-free phospholipid was obtained. (The phosphatidyl-ethanolamine content of this Fraction was 0.1% by.
weight or less.~
EX~MPLE
Using a homomixer, 30 g of purified soybean oil, 1.5 mg of PGE1 and 0.72 g of oleic acid, 1.5 g of glycerin J.P. (Japanese Pharmacopoeia) and 100 g of distilled water for injection, and 5.4 g of the purified phosphatidylethanolamine-ree phospholipid prepared as in Reference Example 1 were mixed and roughly homogenized.
Then, using a Manton-Gaulin homogenizer, the crude homogenate was further homogenized for 10 minutes under a total stress of 500 kg/cm2. A very delicate homogene-ous PGE1-containing emulsion was obtained by the above procedure. The average particle diameter of the oil drople-ts of this emulsion was 0.2 to 0.4 ~.
XA~P~E 2 The procedure of E~ample 1 was repeated except that 800 ~g of PGF1~ and 0.1 g of linolic acid were used i 25 in place of PGE1 and oleic acid, respectively.

. ~ 12 -1. , ~3!9~73 In this case, a very delicate homogeneous PGF1~-containing emulsion was obtained. The oil droplets of this emulsion had an avera~e particle diameter of 0.2 to 0.4 ~ and no droplets greater than 1 ~ were found.

The procedures of Example 1 were repeated except that 1 mg of PGE2 and 0.2 g of stearic acid were used in place of PGE1 and oleic acid, respectively.
This procedure yielded a very delicate homoge-neous PGE2-con-taining emulsion. The oil droplets of this emulsion had an average particle diameter of 0.2 to 0.4 ~ and no droplets greater than 1 ~ were found.

~%3~

~D

~ ~ ~ ~ ~ U~
t. Ul _, C) ~

o o o o o , ~ `~
~ X
# ~C
.~ ~ E
al ~, ( ~ hO r~
,_ ,o O rC ~ ,a ~ ~ ~ O
E o al ~ o S~ ~ rC O
P.
V ~ lJ y ~ V
, o , o JJ ~ ~ ~ ~ O
0.0 ~ r ~ W
.
.~ .C ,~
E-l ~ c~ U ~u O
:~ ~ E ~
3 ~ ,~
c~ 3 ~ 3 c~ 3 c~ 3 c~ 3 ~ -d c~ ~ C') ~ ~ E sd o o o o o o ~
X X X X X ~ V
u~
C~ ~ oo ~ o o o o o ~ ., P~
3 ~ ,~
, o o ~ a) o o o C ~n o C ~ ~ C C C ,c o . .n ~ ~ L~ C`l .~ C`l P
o ~ o U C~ o ~ o C~ o C~ ~ X

o C~
L~J

~;~3;~

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims

WHAT IS CLAIMED IS:

1. A prostaglandin emulsion composition comprising a prostaglandin emulsified with a phosphatidyl-ethanolamine-free phospholipid.

2. The composition according to Claim 1, wherein said prostaglandin is selected from the group consisting of PGF2.alpha., PGE2, PGD2 PGF1.alpha. PGE1, PGA1, PGI2, PGB1 and the derivatives thereof.

3. The composition according to Claim 2, wherein said derivatives are the alkyl esters of prostaglandins.

4. The composition according to Claim 1, wherein said composition consists essentially of (a) an oil component, (b) a phospholipid component, and (c) water, the proportion of said oil component (a) being about 5 to 50 w/v percent of the total composition and the proportion of said phospholipid component (b) being about 1 to about 50 parts per 100 parts of said oil component (a).

5. The composition according to Claim 1, wherein the proportion of the oil component is 8 to 30 w/v percent of the total emulsion.

6. The composition according to Claim 4, wherein the proportion of said phospholipid component is 5 to 30 parts per 100 parts of said oil component (a).

7. The composition according to Claim 4, wherein said composition further contains an auxiliary emulsifier.

8. The composition according to Claim 7, wherein said auxiliary emulsifier is a fatty acid having 6 to 22 carbon atoms or a physiologically acceptable salt thereof.

9. The composition according to Claim 8, wherein said fatty acid has 12 to 20 carbon atoms.

10. The composition according to Claim 7, wherein said fatty acid is present in a proportion of not more than about 0.3 w/v percent.

11. The composition according to Claim 4, wherein said composition further contains one or more of a member selected from the group consisting of a stabilizer, a high molecular weight compound, and an isotonifying agent.

12. The composition according to Claim 11, wherein said stabilizer is selected from the group consisting of a cholesterol compound in a proportion of not more than 0.5 w/v percent, and phosphatidic acid in a proportion of not more than 5 w/v percent.

13. The composition according to Claim 11, wherein said cholesterol compound is present in a proportion of not more than 0.1 w/v percent and said phosphatidic acid is present in a proportion of not more than 1 w/v percent.

14. A composition according to Claim 11, wherein said high molecular compound is selected from the group consisting of albumin, dextran, a vinyl polymer, a non-ionic surfactant, gelatin and hydroxyethyl-starch in a proportion of 0.1 to 5 weight parts relative to 1 weight part of prostaglandin in the composition.

15. The composition according to Claim 11, wherein the proportion of said member is 0.5 to 1 weight part relative to 1 weight part of prostaglandin in the composition.

16. The composition according to Claim 11, wherein said isotonifying agent is glycerin or glucose.

17. The composition according to Claim 1, wherein said composition contains 0.2 to 100 µg of prostaglandin.

18. The composition according to Claim 4, wherein said oil component is a vegetable oil.

19. The composition according to Claim 18, wherein said vegetable oil is a member selected from the group consisting of soybean oil, cotton seed oil, sesame oil, safflower oil and corn oil.

20. The composition according to Claim 19, wherein said oil component is a high purity soybean oil obtained by steam distillation of purified soybean oil.

21. The composition according to Claim 1, wherein said phosphatidylethanolamine-free phospholipid is a phospholipid fraction obtained from egg yolk or soybean by fractionation with an organic acid and subsequent purifi-cation with an inorganic adsorbent.

22. The composition according to Claims 1 or 21, wherein said phosphatidylethanolamine-free phosphlipid consists predominantly of phosphatidylcholine.

23. The composition according to Claim 13, wherein said albumin is human albumin.

24. The prostaglandin emulsion composition according to Claim 14, wherein said vinyl polymer is polyvinylpyrrolidone.

25. The composition according to Claim 14, wherein said nonionic surfactant is selected from the group consis-ting of polyalkylene glycols, polyoxyalkylene copolymers, hydrogenated castor oil-polyoxyalkylene derivatives and castor oil-polyoxyethylene derivatives.

26. The composition according to Claim 25, wherein said polyoxyalkylene copolymers have an average molecular weight of about 1,000 to about 10,000, said polyoxyalkylene copolymers have an average molecular weight of about 1,000 to about 20,000, said hydrogenated castor oil-polyoxyalkylene derivatives are selected from the group consisting of hydrogenated castor oil-polyoxy-ethylene (40)-ether, (20)-ether and (100)-ether, and said castor oil-polyoxyalkylene derivatives are selected from the group consisting of castor oil-polyoxyethylene (20)-ether, (40)-ether and (100)-ether.